After a little research, I confirmed what you wrote about ARC not being an issue.
The fix was switching the HDMI digital audio outputs for Dolby and DTS from "bitstream" to "PCM".
Problem solved. Thanks for your advice!
P.S.: The audio is much, much better now that the player is doing DAC...
Here is the cable:
https://www.bestbuy.com/site/audioquest-sky-8-4k-ultra-hd-hdmi-cable-black-blue/5794301.p?skuId=5794301
I think it's an 18Gb/s cable. I think the issue is the UHD player is not connected to the sole eARC HDMI input on the TV, and I will be unable to connect through that, as...
My cable is an up-to-date cable, HDMI 2.1.
My TV is "older", a 3-4 year old LG-OLED65E7P. With all its "smart" sound modes and settings, it wouldn't surprise me if the issue originates there.
And no receiver, by the way.
Has anyone else noticed the brief audio dropouts during key lines of dialogue in the 4K discs of "Psycho", "Midsommer: Director's Cut", and the original "Star Wars"?